This invention relates to a binary code which is optically readable by a machine, and in particular, to a binary code which allows for dynamic variability.
Optically readable codes are known in the art. One such code is formed as a "checker board" symbol that represents information in the form of black and white squares. Each square contained within the checker board matrix is of equal size to every other square. Furthermore, the number and size of the squares contained within the matrix is predetermined, accordingly the computer receiving or producing the data expects a specific number of squares contained within the matrix each being of a preset size. This code has not been satisfactory. The code is unable to dynamically expand or contract data capacity to meet changing user requirements without the intervention of re-programming the software of the scanning computer. Accordingly, the user of the code must identify the data requirement prior to implantation of the software system. Additionally, since each square must be of the exact same size and the number of squares is predetermined, the scanning computer must be preset for the expected matrix size thereby limiting the user to a single sized checker board code for each scanner. This necessitates a plurality of code scanners and a system for separating each different sized, different density code and forwarding it to the appropriate scanner.
Codes which overcome these shortcomings by providing indicia associated with the code for informing the computer as to the size of the code are known in the art. One example of such a code is U.S. Pat. No. 3,763,467 which discloses the optical reading of data set up in box fashion upon a card. The card is marked at its periphery with two field defining marks located at the front and trailing edges of the box indicating the size of the field containing binary code decimal data stored within the box. The first row of data within the box, forming the perimeter edge, contains format information identifying which of the columns within the box is to be read. This code has also been less than satisfactory in that it suffers from density and size problems. Even though the size of the field is variable the actual size of the characters within the field is not, accordingly a smaller field size results in smaller amounts of stored information. Furthermore, the size indicia being read must be in a particular location in order to be received and understood by the scanning equipment.
Accordingly, it is desirable to provide a dynamically variable machine optically readable binary code and method for reading and producing thereof which overcomes the shortcomings of the prior art devices described above.